Currently, the irrigation of crops of any nature and irrespective of the location thereof, i.e. in the open air or inside special constructions therefor, by irrigation systems based on the seeping effect of certain types of pipe or conduit available on the market is widely used.
Such pipes or conduits are used for the distribution of the irrigation liquid which, as is known, is formed by water plus the dissolved fertilizers and/or chemicals associated with the irrigation process. Unlike other irrigation systems, such as flooding or sprinkler irrigation, the use of seeping pipes or conduits provides as essential advantages greater uniformity in the distribution of the volume of irrigation liquid and, for like performances, a much smaller volume of such liquid is required, which consequently brings with it a reduction of the overall irrigation process costs.
The seeping pipes and conduits may be laid on the ground surface or buried. The operation and installation variables of such seeping pipes or conduits are adapted to the features required by each particular application, with regard to the flowrate of irrigation liquid supplied and the depth of installation.
The seeping pipes or conduits currently available for use in irrigation systems may be classified, generally speaking, by their constituent nature, as follows:
(a) hosepipes formed by a mixture of granulated rubber and low density polythene resins, which pipes are prepared by extruding both said constituent components;
(b) hosepipes of laminated structure prepared by overlaying two or more adhered layers, which are formed by polythene fiber material.
Both said types of hosepipe (a) and (b) suffer from the following drawbacks, either individually or jointly:
to get the irrigation liquid to seep in the majority of normal operating circumstances, it must flow through the said seeping hosepipes turbulently, all of which implies a substantial reduction of the performance of the irrigation system used, particularly with reference to the length of said seeping hosepipes;
a limited tensile and mechanical impact strength, whereby, in view of the regular working conditions to which the seeping hosepipes are subjected, they are frequently broken or torn, thereby generating high maintenance costs;
low mechanical flexibility restricting or preventing their adaptation to the land to be irrigated, making the assembly operations more difficult and thereby increasing the installation costs;
a low resistance to the environmental agents such as fertilizers, roots, bacteria, etc., whereby their working life is relatively short, involving the need to replace the seeping tubes of the irrigation system relatively frequently;
and, in view of their aforesaid low mechanical flexibility, they occupy a large storage space.